The travelers stewed, caught between the trip they were sure they had completed and the sidewalk they could not reach, compelled to confront a question of ethics at, of all places, a subway turnstile.

But first they had to figure out, where had it fallen apart?

They had gotten off their subway train in Midtown Manhattan without incident. They followed a light at the eastern edge of the platform, rode up an escalator and passed through the turnstiles.

Then some turned left, up a small flight of stairs, past a Subway sandwich shop and a shoeshine parlor — both closed. Others went right, where a shuttered locksmith stood at the base of the stairs. This would seem cruel on the way back down.

For there it was, greeting all parties at street level: a pair of roll-down gates, slammed shut.

“I just feel trapped,” said Kate Lingley, 27, from Greenpoint, Brooklyn, weighing her next move. Then she noticed a fellow rider wandering past.

“Here comes another trapped man.”

This is the Fifth Avenue-53rd Street station, where the E and M trains roam, where a certain kind of subway crime could be ethically defensible, and where, for several passengers each night, the only way out of the subway for about an hour was to slip back in.

Beginning at 9 p.m. on weekdays and Saturdays — as several signs on the platforms can attest — the station’s Madison Avenue exits are closed. But an interior gate often remained open about an hour longer, laying the trap that led riders to the escalator, the turnstiles, the gate and, after a few moments of deliberation, the decision: Jump the turnstile to seek another exit? Call for help? Or, for those without unlimited-ride MetroCards, spend a second fare, not to enter the subway system, but to escape it?

First, the explanation. The top level of the station is owned by private companies, whose personnel control the street-level gates. On two recent nights, the gates were closed at or around 9 p.m. The gate on the platform is operated by Metropolitan Transportation Authority workers, who say their shift schedules usually summon them to the station around 9:45 or 10.

“I don’t know why they make the schedule like this,” one worker, Daniel Martinez, said as he locked the gate last Thursday evening. He began his evening at the station at 53rd Street and Lexington Avenue at 9 p.m., he said, and needed to perform several errands there before walking toward Madison Avenue.

“For those 30, 45 minutes,” Mr. Martinez said, “I’m saying to myself, ‘How many times have people gone up and come back down?’ ”

On that night, and another, 48 hours earlier, the answer was about 20. Some paused for minutes at the turnstiles, contemplating a moral calculus that, according to transit officials, appears to be unique to 53rd Street.

Over the course of two weeknights, about half of the riders hurdled over or ducked under the turnstiles. Several cajoled fellow passengers, who had not yet left the subway system, to push the emergency gate open. And the rest swiped their MetroCards, though for some, like Ms. Lingley, the possession of an unlimited-ride card eased the pain.

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What has caused problems is that an interior gate stays open longer than the station's exit beyond it. So passengers, like these, go through the turnstiles and then cannot leave the station. Here, the passenger paid another fare to re-enter the station to find an open exit.CreditRichard Perry/The New York Times

Many travelers chafed, quite reasonably, at being approached by an inquisitive stranger moments after realizing they were cornered. Adam Alicea, 23, was among several who called the station “an easy spot to rob someone.”

But a few offered to talk through their decisions.

One rider, Anthony Thavar, first insisted he would go over the turnstile, then grew paranoid about a possible police effort to root out fare beaters. (He repeatedly asked those near him if they were officers.)

“I’m not going to jump for $2,” he said finally.

He swiped his card. “Insufficient fare,” the machine read. He walked a few steps to the emergency gate, pushed it in vain, then returned to the turnstile. Without a word, he dashed underneath. He did not appear to regret his choice.

“Jumping turnstiles, what’s up!” he shouted gleefully as the escalator carried him away.

In his wake, two Spanish tourists fumbled for quarters beside two MetroCard vending machines, neither of which was accepting credit cards last week. They reached $1.75, before one dug into her pocket, grimacing, for a $10 bill.

For longtime riders, the episode can rattle years of hard-won confidence. New Yorkers are supposed to know their subways. They know which car will deliver them to the base of the desired exit at their stop. They know to leave 15 minutes of travel-time cushion on weekends. So how can the most fundamental of underground acts — leaving — beguile them so?

“The escalators are on,” Julia Tang, 34, said, still incredulous as she considered her options from the wrong side of the turnstile. “It’s got to be open.”

Days after being informed of the station’s quirk, the authority said Tuesday that it had arranged to have the building owners keep the street-level entrances open until 9:45 p.m. It also planned to rewrite station signs to reflect the change.

Asked if the authority could condone the turnstile jumping that preceded the shift, Charles Seaton, an agency spokesman, said, “I cannot, and I will not.”

But a brief survey of local experts on ethical matters yielded a unanimous result: There is no shame in jumping, given the circumstances. Jason Shelowitz, the artist whose guerrilla “subway etiquette” campaign in 2010 urged riders to keep loud music, nail-clipping and groping off the rails, said any potential ticket would be “an easy one to talk your way out of” with an officer.

Jonathan Haidt, a professor of business ethics at the New York University Stern School of Business, said, “The ethical move is clearly to jump the turnstile.”

“They are not trying to steal service,” he added. “They are simply trying to exit a system that they paid once to enter.”

But Mr. Martinez, the station worker, issued perhaps the most decisive verdict, moments after completing his sweep near the roll-down gates, to ensure that no stragglers remained.

What, he was asked, should riders do before he or a colleague arrived the next night?